I just came across a great New York Times piece on the mail service in the Victorian era. It's full of trivia: for example, did you know that in 1889 London, mail was delivered TWELVE TIMES A DAY? Read this:
In Victorian London, though service wasn't
The original article by the NYTimes:
The Birth of Cheap Communication (and Junk Mail) - By Randall Stross
https://www.nytimes.com/2010/02/21/business/21digi.html